[pve-devel] [PATCH] fix CVE-2016-3955

[Thomas Lamprecht]

Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
---
 ...55-usbip-fix-potential-out-of-bound-write.patch | 45 ++++++++++++++++++++++
 Makefile                                           |  1 +
 2 files changed, 46 insertions(+)
 create mode 100644 CVE-2016-3955-usbip-fix-potential-out-of-bound-write.patch

diff --git a/CVE-2016-3955-usbip-fix-potential-out-of-bound-write.patch b/CVE-2016-3955-usbip-fix-potential-out-of-bound-write.patch
new file mode 100644
index 0000000..d3f9fd0
--- /dev/null
+++ b/CVE-2016-3955-usbip-fix-potential-out-of-bound-write.patch
@@ -0,0 +1,45 @@
+From b348d7dddb6c4fbfc810b7a0626e8ec9e29f7cbb Mon Sep 17 00:00:00 2001
+From: Ignat Korchagin <ignat.korchagin at gmail.com>
+Date: Thu, 17 Mar 2016 18:00:29 +0000
+Subject: USB: usbip: fix potential out-of-bounds write
+
+Fix potential out-of-bounds write to urb->transfer_buffer
+usbip handles network communication directly in the kernel. When receiving a
+packet from its peer, usbip code parses headers according to protocol. As
+part of this parsing urb->actual_length is filled. Since the input for
+urb->actual_length comes from the network, it should be treated as untrusted.
+Any entity controlling the network may put any value in the input and the
+preallocated urb->transfer_buffer may not be large enough to hold the data.
+Thus, the malicious entity is able to write arbitrary data to kernel memory.
+
+Signed-off-by: Ignat Korchagin <ignat.korchagin at gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
+---
+ drivers/usb/usbip/usbip_common.c | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+diff --git a/drivers/usb/usbip/usbip_common.c b/drivers/usb/usbip/usbip_common.c
+index facaaf0..e40da77 100644
+--- a/drivers/usb/usbip/usbip_common.c
++++ b/drivers/usb/usbip/usbip_common.c
+@@ -741,6 +741,17 @@ int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
+ 	if (!(size > 0))
+ 		return 0;
+ 
++	if (size > urb->transfer_buffer_length) {
++		/* should not happen, probably malicious packet */
++		if (ud->side == USBIP_STUB) {
++			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
++			return 0;
++		} else {
++			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
++			return -EPIPE;
++		}
++	}
++
+ 	ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
+ 	if (ret != size) {
+ 		dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
+-- 
+cgit v0.12
+
diff --git a/Makefile b/Makefile
index 6a26e8a..694c01a 100644
--- a/Makefile
+++ b/Makefile
@@ -236,6 +236,7 @@ ${KERNEL_SRC}/README ${KERNEL_CFG_ORG}: ${KERNELSRCTAR}
 	#cd ${KERNEL_SRC}; patch -p1 <../add-empty-ndo_poll_controller-to-veth.patch
 	cd ${KERNEL_SRC}; patch -p1 <../override_for_missing_acs_capabilities.patch
 	#cd ${KERNEL_SRC}; patch -p1 <../vhost-net-extend-device-allocation-to-vmalloc.patch
+	cd ${KERNEL_SRC}; patch -p1 <../CVE-2016-3955-usbip-fix-potential-out-of-bound-write.patch
 	sed -i ${KERNEL_SRC}/Makefile -e 's/^EXTRAVERSION.*$$/EXTRAVERSION=${EXTRAVERSION}/'
 	touch $@
 
-- 
2.1.4